DE102021131794A1 - METHOD OF MAKING A SEMICONDUCTOR STRUCTURE AND SEMICONDUCTOR STRUCTURE - Google Patents

Abstract

A method for producing a semiconductor structure (15) is specified with the following steps: - providing a growth substrate (1), - epitaxially depositing an InGaN semiconductor layer (2), which has InGaN over or on the growth substrate (1), - epitaxially Depositing a further semiconductor layer (4) on the InGaN semiconductor layer (2), the further semiconductor layer (4) having one of the following materials: AlN, AlGaN, GaN,- producing a preliminary structure (10) at least in the further semiconductor layer (4) , side surfaces (11) of the preliminary structure (10) being formed at least partially along an m-plane (9) of a crystal structure of the further semiconductor layer (4), - wet-chemical etching of the preliminary structure (10), with an etching rate in the further semiconductor layer (4 ) is greater along an a-plane (8) of the crystal structure of the further semiconductor layer (4) than along the m-plane (9). A semiconductor structure is also specified.

Description

A method for producing a semiconductor structure and a semiconductor structure are specified.

An improved method for producing a semiconductor structure is to be specified. In particular, an improved method for producing a photonic semiconductor structure is to be specified, which is not provided and set up for generating electromagnetic radiation. Furthermore, an improved semiconductor structure is to be specified which, in particular, is not provided and set up for generating electromagnetic radiation.

These objects are achieved by a method with the steps of patent claim 1 and by a semiconductor structure with the features of patent claim 11.

Advantageous embodiments and developments of the method and the semiconductor structure are specified in the dependent claims.

According to an embodiment of the method for manufacturing a semiconductor structure, a growth substrate is provided. In particular, the growth substrate is suitable for the epitaxial deposition of a semiconductor material. For this purpose, the growth substrate has the same or a similar lattice constant as the semiconductor material that is to be deposited on the growth substrate.

In particular, the growth substrate is monocrystalline. For example, the growth substrate has gallium nitride, sapphire or silicon or consists of one of these materials.

According to a further embodiment of the method, the growth substrate has a hexagonal crystal structure. Typically, the material to be deposited is epitaxially deposited on a c-plane ({0001} plane) of the growth substrate. The semiconductor layers epitaxially deposited on the growth substrate have the same crystal structure and the same orientation of the crystal structure as the growth substrate. Depending on the material composition, only the lattice constants of the epitaxially deposited semiconductor layers can differ from one another and/or from the lattice constant of the growth substrate.

In particular, the growth substrate is provided and set up for the epitaxial deposition of a nitride compound semiconductor material. Nitride compound semiconductor materials are compound semiconductor materials that contain nitrogen, such as the materials from the system In _x Al _y Ga _1-xy N with 0 ≤ x ≤ 1, 0 ≤ y ≤ 1 and x+y ≤ 1.

According to a further embodiment of the method, an InGaN semiconductor layer is deposited epitaxially over or on the growth substrate. The InGaN semiconductor layer includes InGaN or consists of InGaN. In particular, the InGaN semiconductor layer is also based on a nitride compound semiconductor material, with indium being included in the InGaN semiconductor layer. In other words, the InGaN semiconductor layer has a nitride compound semiconductor material according to the above-mentioned formula In _x Al _y Ga _1-xy N or consists of such a nitride compound semiconductor material, where x is not equal to zero.

As used herein, the term “over or on” means that the two elements so related do not necessarily have to be in direct physical contact with one another. Rather, further elements can be arranged in between.

According to a further embodiment of the method, a further semiconductor layer is epitaxially deposited on the InGaN semiconductor layer. The additional semiconductor layer is in direct contact with the InGaN semiconductor layer. In other words, the further semiconductor layer and the InGaN semiconductor layer have a common interface. In particular, the further semiconductor layer has one of the following materials or consists of one of the following materials: AlN, AlGaN, GaN. In particular, the further semiconductor layer is based on a nitride compound semiconductor material which is preferably free of indium. In other words, the further semiconductor layer has a nitride compound semiconductor material according to the abovementioned formula In _x Al _y Ga _1-xy N or consists of such a nitride compound semiconductor material, where x is equal to zero.

According to a further embodiment of the method, a pre-structure is produced at least in the further semiconductor layer, with side surfaces of the pre-structure at least partially along an m-plane ({1 1 00} level) of a crystal structure of the further semiconductor layer are formed. In this case, the crystal structure of the further semiconductor layer is formed in accordance with the crystal structure of the growth substrate and is in particular hexagonal.

In particular, the growth substrate, the InGaN semiconductor layer and the further semiconductor layer usually have the same crystal structure, in particular a hexagonal crystal structure. In addition, the orientation of the crystal structure of the growth substrate, the other semiconductor layer and the InGaN semiconductor layer is also the same. If the InGaN semiconductor layer is epitaxially grown on a c-plane of the growth substrate, a main surface of the InGaN semiconductor layer and a main surface of the further semiconductor layer are also formed as a c-plane. However, the lattice constants of the growth substrate, the InGaN semiconductor layer and the further semiconductor layer differ in the case of different semiconductor materials.

According to a further embodiment of the method, the preliminary structure produced by dry-chemical etching is wet-chemically etched in the further semiconductor layer, with an etching rate in the further semiconductor layer along an a-plane ({1120}-plane) of the crystal structure of the further semiconductor layer being greater than along the m -Level of the further semiconductor layer. In other words, the wet-chemical etching of the preliminary structure takes place selectively with regard to the crystal planes of the further semiconductor layer.

For example, the etching rate in the further semiconductor layer along the a-plane is 10 times to 100,000 times, in particular 100 times to 10,000 times greater than along the m-plane.

• - Bereitstellen eines Wachstumssubstrats,
• - epitaktisches Abscheiden einer InGaN-Halbleiterschicht, die InGaN aufweist über oder auf dem Wachstumssubstrat,
• - epitaktisches Abscheiden einer weiteren Halbleiterschicht auf der InGaN-Halbleiterschicht, wobei die weitere Halbleiterschicht eines der folgenden Materialien aufweist:
  • AlN, AlGaN, GaN,
• - Erzeugen einer Vorstruktur zumindest in der weiteren Halbleiterschicht, wobei Seitenflächen der Vorstruktur zumindest teilweise entlang einer m-Ebene einer Kristallstruktur der weiteren Halbleiterschicht ausgebildet werden,
• - nasschemisches Ätzen der Vorstruktur, wobei eine Ätzrate in der weiteren Halbleiterschicht entlang einer a-Ebene der Kristallstruktur der weiteren Halbleiterschicht größer ist als entlang der m-Ebene.

According to a preferred embodiment, the method comprises the following steps:

• - providing a growth substrate,
• - epitaxially depositing an InGaN semiconductor layer comprising InGaN over or on the growth substrate,
• - epitaxial deposition of a further semiconductor layer on the InGaN semiconductor layer, the further semiconductor layer having one of the following materials:
  • AlN, AlGaN, GaN,
• - producing a pre-structure at least in the further semiconductor layer, with side surfaces of the pre-structure being formed at least partially along an m-plane of a crystal structure of the further semiconductor layer,
• - Wet-chemical etching of the preliminary structure, wherein an etching rate in the further semiconductor layer is greater along an a-plane of the crystal structure of the further semiconductor layer than along the m-plane.

The specified steps are preferably carried out in the specified order.

According to a further embodiment of the method, the preliminary structure extends into the InGaN semiconductor layer. In particular, the preliminary structure can also completely penetrate the InGaN semiconductor layer. For example, the preliminary structure extends from the first main area of the InGaN semiconductor layer along a stacking direction of the epitaxial semiconductor layers into the further semiconductor layer and through it.

According to a further embodiment of the method, the preliminary structure is produced by a dry-chemical etching method, such as reactive ion etching (RIE for short: “reactive ion etching”). The preliminary structure produced by the dry-chemical etching process usually has comparatively rough side surfaces.

According to a further embodiment of the method, the InGaN semiconductor layer and the further semiconductor layer are etched simultaneously during the wet-chemical etching. In particular, the InGaN semiconductor layer and the further semiconductor layer are etched simultaneously during the wet-chemical etching if the preliminary structure extends into the InGaN semiconductor layer. In the case of wet-chemical etching, the finished semiconductor structure is formed from the preliminary structure.

One idea of the present application is, to produce an improved semiconductor structure, first to produce the pre-structure in the further semiconductor layer and in particular the InGaN semiconductor layer, for example by dry-chemical etching and to smooth the surface of the pre-structure in a further step by wet-chemical etching. In the case of wet-chemical etching, in particular the etch rate along the a-plane of the crystal structure of the etched semiconductor material has a greater value than along the m-plane of the crystal structure of the etched semiconductor material. In particular, the surfaces of the preliminary structure that run along the m-plane are designed to be as smooth as possible.

According to a further embodiment of the method, the InGaN semiconductor layer is irradiated with electromagnetic radiation during the wet-chemical etching. If the preliminary structure reaches into the InGaN semiconductor layer, the preliminary structure in particular is irradiated with the electromagnetic radiation during the wet-chemical etching. Charge carriers form in the InGaN semiconductor layer as a result of the irradiation, so that an etching rate in the InGaN semiconductor layer during wet-chemical etching is increased compared to an etching rate in the further semiconductor layer. For example, the irradiation increases the etch rate along both the a-plane and the m-plane.

With the help of the irradiation with the electromagnetic radiation, a charge carrier density within the semiconductor material to be etched can be set in a suitable manner and in particular increased, so that the wet-chemical etching is optimized.

According to a further embodiment of the method, an energy of the electromagnetic radiation with which the InGaN semiconductor layer is irradiated during the wet-chemical etching is greater than a band gap of the semiconductor material of the InGaN semiconductor layer and smaller than a band gap of the semiconductor material of the further semiconductor layer.

For example, the InGaN semiconductor layer is irradiated with electromagnetic radiation using a laser, in particular using a fanned-out laser. A laser offers the advantage of generating electromagnetic radiation with a comparatively well-defined electromagnetic radiation. In particular, the laser usually produces monochromatic light.

According to a further embodiment of the method, during the wet-chemical etching of the pre-structure from the InGaN semiconductor layer, self-supporting columns are formed which carry a hexagonal structure from the further semiconductor layer.

For example, at least one of the following materials is used as an etchant in wet-chemical etching: tetramethylammonium hydroxide (TMAH), KOH.

According to a further embodiment of the method, the InGaN semiconductor layer and/or the further semiconductor layer has a thickness of between 10 nanometers and 2000 nanometers inclusive. The InGaN semiconductor layer and/or the further semiconductor layer particularly preferably has a thickness of between 100 nanometers and 900 nanometers inclusive.

The method described here is intended and set up to produce a semiconductor structure. All features and embodiments that are described here in connection with the method can therefore also be formed in the semiconductor structure and vice versa.

In accordance with a further embodiment, the semiconductor structure has a structure which has one of the following materials or consists of one of the following materials: AlN, AlGaN, GaN. In particular, the structure is formed from a nitride compound semiconductor material free of indium. In other words, the nitride compound semiconductor material obeys the structure of the formula In _x Al _y Ga _1-xy N, where x=0.

In accordance with a further embodiment, the semiconductor structure comprises pillars which support the structure and are mechanically stably connected to a substrate. In particular, the pillars are in direct contact with the structure. The structure and the pillars are each formed of semiconductor layers epitaxially grown in a stacking direction. In particular, the columns have a main extension direction in the direction of the stacking direction of the epitaxial semiconductor layers. In particular, the pillars have InGaN or consist of InGaN and are in direct contact with the structure.

The substrate can be a growth substrate of the structure and/or the pillars. However, it is also possible for the substrate to be an active, light-generating semiconductor component, for example a light-emitting diode or a laser diode. In this case, the semiconductor structure and the active, light-generating semiconductor component can be monolithically integrated. Furthermore, the semiconductor structure can also be monolithically integrated into a transistor.

In particular, the pillars are arranged between the structure and the growth substrate. The growth substrate is a growth substrate for the semiconductor material of the structure and/or the columns.

According to a further embodiment of the semiconductor structure, side faces of the structure are formed at least partially along an m-plane of a crystal structure of the structure. In particular, the side surfaces run along the stacking direction of the epitaxial layers.

According to a preferred embodiment, the semiconductor structure comprises a structure comprising AlN, AlGaN and/or GaN, and pillars which support the structure and connect it mechanically stably to a growth substrate, the pillars comprising InGaN and being in direct contact with the structure, and Side surfaces of the structure are at least partially formed along an m-plane of a crystal structure of the structure.

In particular, the structure is a passive structure that is not provided and designed to generate electromagnetic radiation. The structure is therefore preferably free of an active layer that is set up and provided for generating electromagnetic radiation.

According to one embodiment, the structure is a photonic structure. For example, the structure is comprised of a photonic integrated circuit. In the present case, the term “photonic structure” means in particular that the structure is photonically effective, ie that it acts on photons. For example, the photonic structure is suitable for waveguiding electromagnetic radiation.

For example, the semiconductor structure is based on a nitride compound semiconductor material or is formed by one or more nitride compound semiconductor materials.

Preferably, the structure is mechanically connected to the substrate only through the pillars, while areas located between the pillars and delimited in the stacking direction by the substrate and the structure are filled with air. In this way, the structure can be optically decoupled particularly well from the substrate.

According to a further embodiment of the semiconductor structure, the side faces of the structure are at least partially, preferably completely, atomically smooth. In particular, it is possible with the aid of the present method to achieve a structure with largely atomically smooth side surfaces.

In accordance with a further embodiment of the semiconductor structure, main areas of the structure are also formed in an atomically smooth manner. The major faces of the structure have the stacking direction as the face normal. An atomically smooth design of the side surfaces and/or the main surfaces of the structure leads in particular to a particularly good photonic function of the structure.

For example, the structure is a ring resonator. A ring resonator is used, for example, in a laser diode as a resonator for forming a standing wave of electromagnetic radiation in a laser-active medium. In this case, the structure can be mechanically connected to the columns with a laser-active medium as the substrate and, in particular, integrated monolithically.

Electromagnetic radiation, for example from a laser-active medium that is guided in the ring resonator, is reflected in particular on the side surfaces of the structure that run along the m-plane and is guided by the jump in refractive index on the main surfaces between the semiconductor material and the ambient air.

For example, the structure has a closed ring shape in plan view. In particular, the closed ring shape can be a closed ring with a hexagonal shape. In this case, the structure is preferably mechanically connected to the substrate at each corner of the hexagon with a column. Such a structure is particularly suitable as a ring resonator.

In accordance with a further embodiment of the semiconductor structure, the structure is set up for conducting electromagnetic radiation which is coupled into the structure. In other words, the structure is designed as a waveguide for conducting electromagnetic radiation.

• Die 1 bis 8 zeigen schematische Darstellungen von Stadien eines Verfahrens zur Herstellung einer Halbleiterstruktur gemäß einem Ausführungsbeispiel.
• 9 zeigt eine schematische Darstellung einer Halbleiterstruktur gemäß einem Ausführungsbeispiel.
• 10 zeigt eine schematische Darstellung einer Halbleiterstruktur gemäß einem weiteren Ausführungsbeispiel.
• 11 zeigt exemplarisch eine rasterelektronenmikroskopische Aufnahme einer Halbleiterstruktur.

Further advantageous embodiments and developments of the semiconductor structure and the method for its production result from the exemplary embodiments described below in connection with the figures.

• The 1 until 8th show schematic representations of stages of a method for producing a semiconductor structure according to an embodiment.
• 9 12 shows a schematic representation of a semiconductor structure according to an embodiment.
• 10 shows a schematic representation of a semiconductor structure according to a further embodiment.
• 11 shows an example of a scanning electron micrograph of a semiconductor structure.

Elements that are the same, of the same type or have the same effect are provided with the same reference symbols in the figures. The figures and the relative sizes of the elements shown in the figures are not to be regarded as being to scale. Rather, individual elements, in particular layer thicknesses, can be shown in an exaggerated size for better representation and/or for better understanding.

In the method according to the embodiment of 1 until 8th a growth substrate 1 is first provided in a first step ( 1 ). The growth substrate 1 is set up for the epitaxial deposition of a semiconductor layer sequence. In particular, the growth substrate 1 is set up for the epitaxial growth of a nitride compound semiconductor material. For example, the growth substrate 1 is gallium nitride, sapphire or silicon.

In a further step, an InGaN semiconductor layer 2 is formed on the growth substrate 1 deposited epitaxially. In the present case, the InGaN semiconductor layer 2 is epitaxially deposited in direct contact on a main surface 3 of the growth substrate 1 . In this case, the InGaN semiconductor layer 2 has InGaN or is formed from InGaN. Specifically, the InGaN semiconductor layer 2 is formed of a nitride compound semiconductor material including indium.

In a further step, a further semiconductor layer 4 is epitaxially deposited in direct contact on the InGaN semiconductor layer 2 ( 2 ). The further semiconductor layer 4 has one of the following materials or consists of one of the following materials: AlN, AlGaN, GaN. In contrast to the InGaN semiconductor layer 2, the further semiconductor layer 4 is formed from a nitride compound semiconductor material that is free of indium.

The growth substrate 1, the InGaN semiconductor layer 2 and the further semiconductor layer 4 have a hexagonal crystal structure. In particular, the main surface 3 of the growth substrate on or over which the InGaN semiconductor layer 2 is epitaxially deposited has a c-plane ({0001}-plane) 5 . A main area 6 of the InGaN semiconductor layer 2 and a main area 7 of the further semiconductor layer are also each formed as a c-plane 5 .

A unit cell of the hexagonal crystal structure is exemplified in 3 shown. The unit cell of the hexagonal crystal structure has a c-plane ({0001} plane) 5, an a-plane ({1120} plane) 8, and an m-plane ({1 1 00} level) 9 on. The a-plane 8 runs inside the unit cell.

In a further step, a preliminary structure 10 is produced in the InGaN semiconductor layer 2 and in the further semiconductor layer 4 and the InGaN semiconductor layer, side surfaces 11 of the preliminary structure 10 being at least partially along the m-plane 9 of the crystal structure of the InGaN semiconductor layer 2 and the further Semiconductor layer 4 are formed ( 4 ). In particular, in the present exemplary embodiment, the preliminary structure 10 is produced by a dry-chemical etching method, for example by reactive ion etching. Here, the side surfaces 11 of the preliminary structure 10 are formed rough ( 6 ) .

In the present case, the preliminary structure 10 extends completely through the InGaN semiconductor layer 2 and the further semiconductor layer 4 to the growth substrate 1 ( 5 ). The preliminary structure 10 according to the embodiment of FIG 5 is formed in a ring shape in a plan view of the growth substrate 1 . In particular, the preliminary structure 10 is designed as a closed ring with a uniform hexagonal shape when viewed from above. An angle α between respectively directly adjacent legs 22 of the hexagonal preliminary structure 10 is 120° in the present case. The side faces 11 of the preliminary structure 10 run along the m-plane 9 of the hexagonal crystal structure of the InGaN semiconductor layer 2 and the further semiconductor layer 4.

In the present case, the preliminary structure 10 is formed from material of the further semiconductor layer 4 and the InGaN semiconductor layer 2 , the material of the further semiconductor layer 4 completely covering the InGaN semiconductor layer 2 . In particular, the main area 6 of the InGaN semiconductor layer 4 of the preliminary structure 10 is completely covered with the material of the further semiconductor layer 4 .

In a further step, the preliminary structure 10 is wet-chemically etched with an etchant 12 ( 7 ). In the case of wet-chemical etching, an etching rate in the further semiconductor layer 4 along the a-plane 8 of the crystal structure of the further semiconductor layer 4 is greater than along the m-plane 9 , atomically smooth. For example, TMAH and/or KOH is used as the etchant 12 in the wet-chemical etching.

During the wet-chemical etching, the preliminary structure 10 is simultaneously irradiated with electromagnetic radiation 13, which is generated by a laser, for example. As a result, charge carriers are generated in the InGaN semiconductor layer 2 so that an etching rate in the InGaN semiconductor layer 2 is increased compared to the further semiconductor layer 4 . As a result, pillars 14 are formed at the corners of the ring-shaped preliminary structure 10 during wet-chemical etching, and are mechanically stably connected to the growth substrate 1 . The columns 14 are formed at the corners of the preliminary structure 10, since the preliminary structure 10 is somewhat wider here.

In the present method, both atomically smooth side surfaces 11 of the preliminary structure 10 and columns 14 made of the indium-containing nitride compound semiconductor material of the InGaN semiconductor layer 2 are produced by the simultaneously occurring wet-chemical etching with the etchant 12 and the irradiation with electromagnetic radiation 13 ( 8th ).

The semiconductor structure 15 according to the embodiment of FIG 9 has a substrate 16 . In the present case, the substrate 16 comprises a laser-active medium, for example an active epitaxially grown layer 17 suitable for generating radiation. The active layer 17 comprises, for example, a pn junction, a double heterostructure, a single quantum well or in particular prefers a multiple quantum well (MQW) structure for generating electromagnetic radiation. The term quantum well structure does not contain any information about the dimension of the quantization. It thus includes, inter alia, quantum wells, quantum wires and quantum dots and any combination of these structures.

A structure 19 is also arranged on a main surface 18 of the substrate 16 and is mechanically stably connected to the substrate 16 via columns 14 . In this case, the columns 14 are in direct contact both with the structure 19 and with the substrate 16 . The structure 19 is formed in particular from a nitride compound semiconductor material which is free of indium. For example, the structure 19 is formed from one or more of the following materials: AlN, AlGaN, GaN.

In the present case, the structure 19 is ring-shaped with a hexagonal basic shape that is uniform when viewed from above. The hexagonal structure 19 is mechanically stably connected to the substrate 16 by a column 14 at each corner. Areas 20 between two directly adjacent columns 14, which are delimited by the structure 19 and the substrate 16, are filled with air.

In the present case, the structure 19 is not designed to generate electromagnetic radiation. The structure 19 serves in particular as a ring resonator for electromagnetic radiation that is generated in the active layer 17 of the substrate 16 . Since the structure 19 is connected to the substrate 19 only via the columns 14 at the corners, a particularly good optical decoupling between the substrate 16 and the structure 19 is ensured. Furthermore, the structure 19 has atomically smooth surfaces on side surfaces 21 which are aligned along the m-plane of the crystal structure of the structure 19 . In this way, electromagnetic radiation coupled into the structure 19 can be reflected particularly efficiently and largely without radiation loss at the side surfaces 21 . The reflection at the side surfaces 21 leads to the formation of a standing wave of coupled electromagnetic radiation in the ring-shaped structure 19. The quality of the ring resonator is therefore increased due to the crystallographically smooth m-planes 9 of the side surfaces 21. The structure 19 designed as a ring resonator is still almost self-supporting.

The semiconductor structure 15 according to the embodiment of FIG 10 has a substrate 16, which in the present case is in the form of a growth substrate 1 for epitaxially grown columns 14 and an epitaxially grown structure 19. In the present case, the columns 14 connect the structure 19 to the growth substrate 1 in a mechanically stable manner. For example, the semiconductor structure 15 according to the embodiment of FIG 10 Be part of a photonic circuit. Furthermore, the structure 19 of 10 also on the substrate 16 of the semiconductor structure 15 according to the embodiment of FIG 9 be arranged. Furthermore, designed as a waveguide structure 19 of 10 also to the structure 19 designed as a ring resonator 9 to be connected.

In the present case, the structure 19 is formed from a nitride compound semiconductor material which is free of indium. In the present case, the structure 19 comprises legs 22 formed in a straight line, which run along lattice planes of the hexagonal crystal structure of the nitride compound semiconductor material. Legs 22 of the structure 19 are arranged in a zigzag shape. An angle α between two directly adjacent straight legs 22 of the structure 19 has a value of approximately 120° in the present case. In other words, designed as a waveguide structure 19 according to 10 executed in a hexagonal zigzag shape. In contrast to the semiconductor structure 15 according to the embodiment of FIG 9 is the structure 19 according to the embodiment of FIG 10 not closed.

At the corners, the zigzag structure 19 is mechanically stably connected to the growth substrate 1 by columns 14 . In the present case, the columns 14 are formed by an indium-containing nitride compound semiconductor material. Regions 20 between two directly adjacent columns 14, which are delimited by a main surface of the structure 19 and a main surface 3 of the growth substrate 1, are filled with air in the present case. The waveguiding structure 19 according to the 10 is therefore designed almost self-supporting and mechanically supported only by the columns 14 at the corners.

The scanning electron micrograph according to the 11 Fig. 13 shows a wet-chemically etched m-plane 8 of another semiconductor layer 4 comprising GaN and an InGaN semiconductor layer 2 placed in direct contact with each other. The scanning electron micrograph shows, on the one hand, that the m-level 8 of the further semiconductor layer 4 and the InGaN semiconductor layer 2 is crystallographically smooth and, on the other hand, that the InGaN semiconductor layer 2 exhibited an increased etching rate during wet-chemical etching, since the InGaN semiconductor layer 2 is withdrawn. The InGaN semiconductor layer 2 was etched while being irradiated with electromagnetic radiation 13 .

The features and embodiments described in connection with the figures be combined with one another according to further exemplary embodiments, even if not all combinations are explicitly described. Furthermore, the exemplary embodiments described in connection with the figures can alternatively or additionally have further features in accordance with the description in the general part.

The invention is not limited to these by the description based on the exemplary embodiments. Rather, the invention encompasses every new feature and every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.

Reference List

1

growth substrate

2

InGaN semiconductor layer

3

main surface of the growth substrate

4

another semiconductor layer

5

c level

6

Main surface of the InGaN semiconductor layer

7

Main surface of the further semiconductor layer

8th

a level

9

m level

10

substructure

11

side surface of the preliminary structure

12

Etch

13

electromagnetic radiation

14

pillar

15

semiconductor structure

16

substrate

17

active layer

18

main surface of the substrate

19

structure

20

Area

21

side surface of the structure

22

leg

a

angle

Claims (15)

Method for manufacturing a semiconductor structure (15) with the following steps: - providing a growth substrate (1), - epitaxial deposition of an InGaN semiconductor layer (2), which has InGaN over or on the growth substrate (1), - epitaxial deposition of a further semiconductor layer (4) on the InGaN semiconductor layer (2), the further semiconductor layer (4) having one of the following materials: AlN, AlGaN, GaN, - Production of a pre-structure (10) at least in the further semiconductor layer (4), side surfaces (11) of the pre-structure (10) being formed at least partially along an m-plane (9) of a crystal structure of the further semiconductor layer (4), - Wet-chemical etching of the preliminary structure (10), an etching rate in the further semiconductor layer (4) along an a-plane (8) of the crystal structure of the further semiconductor layer (4) being greater than along the m-plane (9). Method according to the preceding claim, in which the preliminary structure (10) extends into the InGaN semiconductor layer (2). Method according to one of the above claims, in which the preliminary structure (10) is produced by a dry-chemical etching method. Method according to one of the above claims, in which the InGaN semiconductor layer (2) and the further semiconductor layer (4) are etched simultaneously during the wet-chemical etching. Method according to one of the above claims, in which the InGaN semiconductor layer (2) is irradiated with electromagnetic radiation (13) during the wet-chemical etching, so that charge carriers form in the InGaN semiconductor layer (2) and an etching rate in the InGaN semiconductor layer (2) is increased in wet chemical etching. Method according to the preceding claim, in which an energy of the electromagnetic radiation (13) is greater than a band gap of the semiconductor material of the InGaN semiconductor layer (2) and smaller than a band gap of the semiconductor material of the further semiconductor layer (4). Procedure according to one of Claims 5 until 6 , in which the InGaN semiconductor layer (2) is irradiated with a laser. Method according to one of the above claims, in which the wet-chemical etching of the preliminary structure (10) from the InGaN semiconductor layer (2) produces self-supporting columns (14) which carry a hexagonal structure (19) from the further semiconductor layer (4). Method according to one of the above claims, wherein in the wet chemical etching at least one of the following materials is used as the etchant (12): tetramethylammonium hydroxide (TMAH), KOH. Method according to one of the above claims, in which the InGaN semiconductor layer (2) and/or the further semiconductor layer (4) has a thickness of between 10 nanometers and 2000 nanometers inclusive. Semiconductor structure (15) with: - a structure (19) comprising one of the following materials: AlN, AlGaN, GaN, - Columns (14) that carry the structure (19) and connect to a substrate (16) mechanically stable, wherein - the pillars (14) comprise InGaN and are in direct contact with the structure (19), and - Side surfaces (21) of the structure (19) are formed at least partially along an m-plane (9) of a crystal structure of the structure (19). Semiconductor structure (15) according to the preceding claim, in which the side face (21) of the structure (19) is at least partially, preferably completely, atomically smooth. Semiconductor structure (15) according to one of Claims 11 until 12 , in which the structure (19) is not designed to generate electromagnetic radiation. Semiconductor structure according to one of Claims 11 until 13 , In which the structure (19) is designed as a ring resonator. Semiconductor structure according to one of Claims 11 until 14 , in which the structure (19) for conducting electromagnetic radiation, which is coupled into the structure (19), is set up.

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